Both Gathers and Kimble were recruited to the University of Southern California by Head Coach Stan Morrison and his top assistant, David Spencer. They were joined by high school All-American, Tom Lewis, and Rich Grande as the "Four Freshmen" star recruiting class.[2][3] Following an 11–17 season coaching USC, Morrison and Spencer were fired after the 1985-86 season, despite winning the Pac-10 Conference the previous year. It was reported that the players would not remain unless certain conditions were met, including having a say in the next coaching staff.[2]

USC hired George Raveling as the next head coach of the Trojans.[4] Raveling gave the players a deadline to respond whether they would remain on the team. When they did not respond, he revoked the scholarships of Gathers, Kimble, and Lewis.[5] Raveling's controversial[6] statement was, "You can't let the Indians run the reservation," he said. "You've got to be strong, too. Sometimes you have to tell them that they have to exit."[2] Kimble and Gathers transferred together from USC to Loyola Marymount. Lewis transferred to Pepperdine. Grande remained at USC.[7]

Due to NCAA regulations, Gathers and Kimble could not play in the season following their transfer. They helped lead the Lions to a 28–4 record in 1987–88.[8] Gathers led the team that year in both scoring and rebounding (averaging 22.5 points and 8.7 rebounds per game), was named to the All-West Coast Conference (WCC) first team, and was awarded the WCC Tournament Most Valuable Player (MVP).[9][10] In the 1988–89 season, Gathers became the second player in NCAADivision I history to lead the nation in scoring and rebounding in the same season, averaging 32.7 points and 13.7 rebounds per game.[8][11] He was named WCC Player of the Year and again won the WCC Tournament MVP.[10] On December 30, 1988, he scored a career-high 49 points along with 26 rebounds in a 130–125 win over Nevada.[12]

As a senior in 1989–90, he was a candidate for player of the year and had been projected as an NBA lottery pick.[11] Gathers' head coach while at LMU, Paul Westhead, had instituted an extraordinarily fast-paced game plan. On offense, the Lions took numerous three-point shots, and typically shot the ball within 10 seconds of gaining possession. Their defense was a full-court press designed to force their opponents into a frenzied up-and-down game. Gathers' teams led Division I in scoring in 1988 (110.3 points per game), 1989 (112.5), and 1990 (122.4).[13] LMU's 122.4 point per game in 1990 is still a record as of April 2012.[14] As of April 2012, Loyola Marymount held the five highest combined score games in Division I history. Four of the five occurred during Gathers' career, including a record 331 in the 181–150 win over United States International University on January 31, 1989.[8][15]

At 6'7" and 210 pounds, Gathers was Loyola Marymount's strongest inside player. He had a high field goal percentage because he seldom shot from beyond 10 feet. He used his power and quickness for follow-up baskets and scoring on fast breaks. "I don't care much about the points," said Gathers. "In fact, I should lead the nation in scoring because of my rebounding. Anybody can score 30 points a night if that's what he's concentrating on. But rebounding is special because it comes from the heart."[8]

On December 9, 1989, Gathers collapsed at an LMU home game against UC Santa Barbara.[16] He was found to have an abnormal heartbeat (exercise-induced ventricular tachycardia), and was prescribed a beta blocker, Inderal.[16] However, Gathers felt that the medication adversely affected his play, and his dosage was gradually cut back.[17] After missing three games, he struggled with his play for weeks after returning. His play recovered in a nationally televised game against LSU on February 3, 1990, when he scored 48 points along with 13 rebounds while being guarded by future NBA first-round draft picks Stanley Roberts and Shaquille O'Neal in a 148–141 overtime loss.[12][18] The Lions won seven of their next eight games,[18] and Gathers recorded a career-high 30 rebounds against Saint Mary's.[12]

As the West Coast Conference (WCC) Tournament neared, Gathers did not show up for repeated appointments to test if the reduced medication was still suppressing the arrhythmias. It was suspected Gathers was not taking any dosage on game days.[16] On Sunday, March 4, 1990, in Los Angeles, he collapsed again with 13:34 left in the first half of the WCC tournament semifinal game against the Portland Pilots. He had just scored a dunk on an alley-oop pass from point guard Terrell Lowery that put the Lions up 25–13.[11][17] He collapsed a yard or two away from Pilots point guard Erik Spoelstra.[19] He attempted to get up, telling the athletic trainers, "I don't want to lay down!" Shortly after, he stopped breathing.[20] Gathers was pronounced dead at a nearby hospital at 6:55 PM PST.[21] He was 23 years old.[16]

Minutes after Gathers was taken to the hospital, the WCC commissioner suspended the game indefinitely.[22]ESPN broadcast graphic footage of Gathers' collapse on SportsCenter;[23] the network was at the game recording advance footage for the championship game it was scheduled to televise the next night. Late that night, the WCC canceled the tournament and awarded Loyola the conference's automatic bid to the NCAA Tournament due to its WCC regular season title.[24]

An autopsy found that he suffered from a heart-muscle disorder, hypertrophic cardiomyopathy.[16] Gathers' family later filed a $32.5 million lawsuit charging negligence.[25] Loyola Marymount settled out of court for $1.4 million, while the cardiologist who treated Gathers settled for $1 million.[26][27]

Loyola Marymount was placed in the West Region as the #11 seed in that season's NCAA tournament. During LMU's subsequent run to the Elite Eight before falling to eventual national champion UNLV, Kimble—a right-handed player—shot his first free throw of each game left-handed in memory of Gathers, who, while naturally right-handed, was a poor free-throw shooter and had, for a time, attempted to shoot left-handed.[28] Kimble made all three attempts (he did not have any free-throw attempts in the Sweet 16 win over Alabama); from that point onward, and deep into his professional career, Kimble continued to honor Gathers by taking his first free throws left-handed.

Gathers was named a consensus second-team All-America and first team All-WCC selection for the season.[10][29] He finished his career averaging 28.0 points and making 59 percent of his field goals, which were both school records as of 2010. He also averaged 11.1 rebounds for his career. He was voted WCC Player of the Decade for the 1980s.[30]

Gersten Pavilion, LMU's on-campus athletics facility, is known to Lions fans as "Hank's House", although that is not part of its official name.[32][33] His number 44 jersey was retired by LMU in 2000.[30] On January 29, 2005, the entire 1989–90 team was inducted into Loyola Marymount's Hall of Fame during halftime of a 63–46 win over cross-town rival Pepperdine. Gathers' mother, Lucille Gathers Cheeseboro, attended the ceremony.[34]

Gathers was part of the storyline in the ESPN film Guru of Go about Westhead, part of their 30 for 30 series.[37]

Gathers' death reemerged in national news wires during the 2016 NBA Playoffs when Kimble, interviewed for the celebrity gossip website TMZ.com, urged that Miami Heat star Chris Bosh retire for health reasons. Bosh has been suffering from blood clotting issues that forced him to miss the last several months of both the 2014–15 and 2015–16 seasons, as well as the entirety of the 2016–17 season. While Bosh felt that he was healthy enough to continue playing, Kimble disagreed:[38]

There are so many other things he could do with his life. Hank Gathers had the same thing, Hank could have been a comedian, and actor or did speaking engagements. It's not worth the risk. I would just say absolutely not, don't do it. If Hank had the ability to do it again he wouldn't have paid the ultimate price ... I am sure [Bosh] has children and they are going to need their father around as much as possible.

TMZ also interviewed Gathers' brother Derrick, who agreed with Kimble that Bosh should retire.[38]